PHILADELPHIA (CBS) – With just a month to go until primary day, the four candidates seeking the Democratic nomination for governor have finally started to mix it up among themselves. But a prominent analyst thinks the challengers will have to crank it up more if they want to catch the leader.

Only recently have some of the other Democratic candidates taken aim at frontrunner Tom Wolf.

Allyson Schwartz has questioned an over $4-million bank loan wealthy businessman Wolf has taken to help finance his campaign. And Rob McCord has attacked Wolf for a less aggressive proposal to tax natural gas extraction.

But Franklin and Marshall College pollster and political analyst Terry Madonna believes the Democratic contest remains fairly tame, and that the challengers will have to turn it up more if they are to catch Wolf:

“The campaign has definitely turned more negative. Is it enough to move voters? I seriously doubt it.”

If the poll numbers change, Madonna believes it will be more likely because the challengers have increased their name recognition through more advertising but thinks that alone won’t be enough.